1. Field of the Invention
The present invention relates to an image capturing of a USB(Universal Serial Bus) camera and more particularly, to a device for managing a snap shot in a USB camera, which is suitable for implementing a snap shot mode; and a method therefor.
2. Field of the Invention
In general, the USB(Universal Serial Bus) is spot lighted as a standard for a serial bus in a PC system. In order to integrate a variety of peripheral interfaces to a PC system, including PS/2, RS232C, parallel ports, and the like, a standard specification of the USB is provided. Being a bus capable of supporting 12 Mbps at the maximum, the USB is paid attention as a PC system of the next generation because the USB allows connection of 63 devices thereto. The USB allows various peripheral devices, such as a camera and a printer, to be used connected to a computer, i.e., a USB host. There is an interface unit between the peripheral devices and the USB host for interfacing function.
A related art method for managing a snap shot in a USB camera will be explained with reference to the attached drawings. The method requires synchronizing patterns indicating a start and an end of the image. In a frame unit transmission of the images, a synchronizing signal generating unit 13a provided in the interface unit 13 inserts the sync pattern between frames, permitting the USB host 15 to detect the start and the end of the image with easy. A performance of the USB host 15 will be degraded if the sync pattern is not inserted because the USB host 15 is required to conduct much operation for distinguishing between frames. Thus, the insertion of the sync pattern prevent the degradation of the USB host 15 performance.
The foregoing related art method for managing a snap shot in a USB camera will be explained in detail. FIG. 2 illustrates an operation timing diagram showing the related art snap shot implementation.
The camera 11 digitizes an image and forwards to an interface unit 13 through an end point exclusive for video. The interface unit 13 inserts a sync pattern between frames for indicating a start or an end of an image. Upon pressing a snap shot button 11a fitted to a camera 11, an image data(frame 3) is provided to the interface unit 13 through the end point exclusive for snap shot. An FIFO(First In First Out) unit 13b in the interface unit 13 stores the image data provided through the end point exclusive for snap shot.
FIG. 1 illustrates a block diagram schematically showing a system for explaining a related art method for managing a snap shot in a USB camera.
Referring to FIG. 1, the system is provided with a camera 1, an interface unit 13, and a USB host 15. There are a plurality of end points between the camera 11 and the interface unit 13; one of which is exclusively used as an end point for a snap shot and another one of which is exclusively used as an end point for image. The camera 11 receives, and digitizes the image and provides to the interface unit 13. And, the interface unit 13 converts the digitized image received through the end point to suit to a USB standard specification, and provides to the USB host 15. The USB host 15 either displays the digitized image on its monitor, or transmits to an opposite USB host (not shown) in a picture communication. As shown in FIG. 1, there are a plurality of end points connected between the camera 11 and the interface unit 113, each of which has a different service; for example, there are an end point exclusive for an image at one side, and an end point exclusive for snap shot at the other side. The end point exclusive for an image transmits a moving picture data digitized in the camera 11. The FIFO unit 13b is provided just in case when the USB host 15 does not sense a pressing of the snap shot button, yet. Thus, provided an image data is stored in the FIFO unit 13b as the snap shot button 11a is pressed, the interface unit 13 provides the data stored in the FIFO unit 13b to the USB host 15 according to request from the USB host 15. Then, the USB host 15, after storing the image data in a hard disk, either displays on a monitor, or provides to other USB host.
However, the method for managing a snap shot in a USB camera has the following problems. That is, the additional end point exclusive for snap shot and the FIFO unit for storage of a video data from the snap shot results in a complicated system, the end point exclusive for snap shot can not be used other than the snap shot, and the USB host should be provided with a complicated driver system and a complicated application program for such an end point exclusive for snap shot.
Accordingly, the present invention is directed to a device for managing a snap shot in a USB camera that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a device for managing a snap shot in a USB camera, in which an existing end point can be used for other service for improving an USB performance.
Another object of the present invention is to provide a device for managing a snap shot in a USB camera, in which one end point is reduced when a snap shot end point is not used for other purpose, for simplifying a system and reducing a chip size.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the Written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the device for managing a snap shot in a USB camera, includes a camera for taking, and digitizing an image, and providing the image through an end point exclusive for an image, an interface unit for inserting either a frame sync pattern between frames of image data provided through an end point exclusive for an image or a snap shot sync pattern instead of the frame sync pattern in a snap shot mode, and a USB host for displaying an image data provided from the interface unit on a monitor in the USB host or forwarding for a picture communication.
In the other aspect of the present invention, there is provided a method for managing a snap shot in a USB camera, including the steps of (1) determining turning on/off of a snap shot button on the camera. (2) according to a result of the determination, either inserting a frame sync pattern between frames of image data and providing to the USB host, or inserting a snap shot sync pattern instead of the frame sync pattern and providing to the USB host, and (3) either displaying an image data having the frame sync pattern or the snap shot sync pattern inserted thereto on a monitor or transmitting the image data to other external USB host
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.